Bottom discharge arrangement

ABSTRACT

The invention relates to a bottom discharge arrangement intended for mounting on goods container of a railway truck. The arrangement includes at least one pair of flaps which is pivotally mounted on the goods container at their mutually remote edges, so as to be able to swing between an open and a closed position in a plane perpendicular to the edges. The arrangement includes a two-arm lever which is common to the link systems and which functions to maneuver the flaps simultaneously. The lever arm is pivotally mounted centrally at a point between the pivot axes of the flaps and is pivotally connected at one end to a first link pivotally mounted on one flap and at the other end is pivotally connected to a second link pivotally mounted on the other flap. When the flaps are closed, the pivot points between the parts of the link system lie in an essentially forceless state of equilibrium in a common plane which is locked in this state of equilibrium by an operating device coacting with the link system. The operating device functions to apply to the two-arm lever a turning moment around its attachment point so as to bring the link system out of its state of equilibrium and therewith allow the flaps to open.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a bottom discharge arrangement intendedfor mounting to a goods containing space, preferably a goods containerof an ore-transporting railway truck.

2. Description of the Prior Art

Known bottom discharge arrangements include so-called sliding flapssupported by carrier arms which in manoeuvering the sliding flaps areable to pivot about a journal pin located above a respective flap andpreferably extending in the longitudinal direction of the truck. As thesliding flaps are manoeuvered, they swing laterally to the transversedirection of the truck and upwards, such as to describe a circular arcwhose centre lies in the pivot axis. When opening and closing thesliding flaps will move along the truck periphery to a position on oneside of the discharge opening, spaced from the journal pin. Thissolution is unsatisfactory, because the sliding flaps cannot be openedvery quickly and because ore tends to collect on the flap surfaces andtherewith prevent the truck from being emptied completely and/or makessubsequent closing of the flaps difficult to achieve. Furthermore,sliding flaps that are mounted in this way are unable to contributetowards guiding the flow of discharged goods into an offloading binplaced beneath the truck and between the wheels thereof.

In order to achieve a well-functioning and quick-operating bottomdischarge arrangement in bottom-discharge ore carrying trucks, orbogies, there is a desire to use flaps which have the form of so-calleddrop flaps, i.e. flaps which when moved to their respective opening andclosing positions do not follow a path along the periphery of the truckto a position on respective sides of the discharge opening, but flapswhose mutually remote edges are pivotally mounted on the bottom of thegoods container and which can therefore be swung rapidly to an openposition in a plane perpendicular to said edges. When closed, theseflaps together form a continuous bottom surface against which the orerests, and when open form a continuation of the mutually opposing wallparts of the goods container located above the flaps and therewithfunction to guide the ore down into the underlying bin.

It has been found convenient to use for manoeuvering the flaps of bottomdischarge arrangements of ore-carrying trucks, or bogies, an eccentricmechanism which is able to lock the flaps in their closed position whenmoved to an "overkneed" position about a rotational centre.

U.S. Pat. No. -A-3,316,859 and U.S. Pat. No. -A-3,611,947 illustrateexamples of bottom discharge arrangements that include an eccentricmechanism which takes a so-called overkneed position when the flaps areclosed. It will be seen, however, that the flaps of these known bottomdischarge arrangements are not drop flaps but sliding flaps, i.e. flapswhich are carried by support arms and which are pivotal about a journalpin mounted above each flap. With this type of flap, no serious problemsoccur as a result of the negative forces that are generated in themanoeuvering mechanism by the weight of the goods being carried when theflaps are closed, because the weight of the ore is taken up essentiallyby the journal pins located above respective flaps and not by the flapoperating mechanism as in the case of drop flaps.

U.S. Pat. No. -A-3,611,947 teaches a bottom discharge arrangement whichincludes a pair of drop flaps which are pivotally mounted on the goodscontainer at their mutually remote edges and operated by means of a linksystem which is common to both flaps and which includes an eccentricmechanism in the form of a two-arm lever pivotally mounted between theflaps. Each end of the lever is pivotally connected to a respective flapby means of a link arm. The eccentric mechanism is in an overkneedposition when the flaps are closed. With the intention of eliminatingthe problem of overcoming negative forces when unlocking the operatingmechanism, the mechanism is constructed so that in the initial unlockingmovement the flaps are moved horizontally from a position in which theyare locked and cannot therefore be pivoted to an end position in whichthe flaps are able to pivot. This arrangement thus obviates the need toovercome the weight of the goods when opening the flaps, and the onlyforce that need be overcome is the frictional force acting between theflaps and those parts of the arrangement that support the flaps.

One drawback with this arrangement is that it does not allow the flapsto open at the speed desired with the inventive bottom dischargearrangement. This is mainly due to the long movement path travelled bythe mechanism from the closed position of the flaps to their upwardlyswung position. Furthermore, the arrangement is structurally complicatedand therewith sensitive to operational disturbances.

OBJECTS AND SUMMARY OF THE INVENTION

The object of the invention is to provide an improved bottom dischargearrangement for all trucks or bogies provided with drop flaps, so as toenable the flaps to be opened more quickly than with known arrangements.Another object of the invention is to provide a bottom dischargearrangement having an operating mechanism which will lock the flapssecurely in their closed positions in spite of a very rapid flap-openingsequence.

These objects are achieved with a bottom discharge arrangement that hasthe features set forth in the following claims.

Because when the flaps are closed, the pivot points between the parts ofthe link system will lie in a generally forceless position ofequilibrium in a common plane, this position of equilibrium being lockedby a manoeuvering device provided in the link system, and because thedevice by means of which the flaps are manoeuvered to an open positionis constructed to apply a rotational moment of force on the two-armlever about its attachment point so as to bring the link system out ofits state of equilibrium, no negative forces will occur as a result ofthe weight of the goods and thus no negative moment of forces will occuraround the rotational centre of the operating mechanism. As a result ofthe construction of the inventive link system, forces that are generatedin the links are guided towards the rotational centre and the forcerequired to open the mechanism is therefore maintained essentiallyconstant irrespective of the weight exerted by the goods.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with reference to anon-limiting embodiment thereof and also with reference to theaccompanying drawings, in which

FIG. 1 is a front view (or rear view) of an ore truck which includes abottom discharge arrangement constructed in accordance with theinvention;

FIG. 2 is a side view of the ore truck provided with the bottomdischarge arrangement according to FIG. 1;

FIG. 3 is a schematic end view of one embodiment of a bottom dischargearrangement, showing the arrangement when open; and

FIG. 4 illustrates the bottom discharge arrangement of FIG. 3 whenclosed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The railway truck 1 illustrated in FIGS. 1 and 2 includes a goodscontainer or basket 2 supported by an undercarriage 3. The truck 1 isintended to transport such goods as ore, coal, etc., and has provided atthe bottom thereof an inventive bottom discharge arrangement 4. Thearrangement 4 includes a pair of mutually identical flaps 5, 5' which,when closed, form a continuous and impervious bottom on which the orerests and which, when open (FIG. 3) define an opening through which theore is discharged to an underlying offloading bin (not shown) locatedbetween the truck wheels (not shown) while guiding the goods into thebin.

The bottom discharge arrangement 4 is mounted on the undercarriage 3 andon the goods container 2 and includes a frame 7 to which the flaps 5, 5'are pivotally connected along their mutually remote edges at 6, 6'. Thebottom discharge arrangement further includes a link system 8 and 8'respectively on each end side of the flaps (see FIG. 2), said systembeing operative to guide the flaps in a plane perpendicular to saidedges as the flaps 5, 5' are opened and closed.

The two link systems 8, 8' are mutually identical and are constructed tomanoeuver the flaps 5, 5' simultaneously.

The link systems 8, 8' are manoeuvered simultaneously by means of anoperating device 9 which includes for each link system an operating arm10 which is pivotally connected at one end to the link system 8, 8' andat its other end to a respective link arm 11, 11', which is, in turn,attached to the respective end of a rotatably journalled axle 12extending along the goods container 2.

As will be seen from FIG. 3, the operating device 9 also includes avertically arranged lifting device 13 which extends in the longitudinaldirection of the truck and which includes a roller 14 for coaction witha guide path (not shown) arranged along the track plane. In theillustrated case, the lifting device 13 is located centrally between thelink systems 8, 8', see FIG. 2.

As will be seen from FIGS. 3 and 4, the lifting device 13 includes apivotal link-arm 15 which extends to a link arm (not shown) fixedlyconnected to the axle 12 and to which the link arm 15 is pivotallymounted. The link arm 15 and the link arm that is not shown are mutuallyarranged so that vertical movement of the roller 14 of the operatingdevice from a lower end position to an upper end position will cause theaxle 12 to turn anti-clockwise. Movement of the roller 14 from its upperend position to its lower end position will cause the axle 12 to turn ina clockwise direction.

Because the two link systems 8, 8' are identical to one another, onlyone of these link systems will be described in the followingdescription.

As shown in FIGS. 3 and 4, the link 8 is placed outside the goodscontainer 2 and includes a bearing block 16 in the region between saidflaps 5, 5', for simultaneous manoeuvering of the flaps. The bearingblock 16 is attached to the goods container 2 and has pivotallyjournalled thereon a two-arm lever 17 which is pivotally connected ateach end to a respective flap 5, 5' through the medium of a link arm 18,19.

For manoeuvering of the link system 8, one end of the manoeuver arm 10is pivotally connected to one end of the two-arm lever 17, while theother end of the manoeuver arm is pivotally attached to the link arm 11,said link arm, in turn, being attached to the end of the axle 12rotatably mounted on the goods container 2.

The pivotal point of the manoeuver arm 10 on the two-arm lever 17 issuch as to enable torque to be applied to the two-arm lever 17 about itsattachment point, thus moving the link system 8 out of its self-lockingposition.

The pivot points of the link arm 11 and the manoeuver arm 10 attached tothe axle 12 are so positioned in relation to one another that rotarymovement of the axle 12 in an anti-clockwise direction will cause theflaps 5, 5' to open, while rotary movement of the axle 12 in a clockwisedirection will cause the flaps 5, 5' to close.

The illustrated embodiment of the bottom discharge arrangement 4 isdesigned for manoeuvering by means of the lifting device 13, which isdescribed in more detail in SE 460 038. It will be understood, however,that the manoeuvering device which drives the link system 8 can bereplaced with other types of drive systems known to the art, such aspiston-cylinder systems for instance.

In order to lock the flaps 5, 5' when they move towards their respectiveclosed positions, the links 17, 18, 19 of the link system 8 are angledin a manner best seen from FIG. 3. The pivotal connections between thelinks 18, 19 and the pivot point of the two-arm lever 17 are spacedapart such that the pivot points of all the parts included in the linksystem will be located in mutually spaced relationship along a line 20(FIG. 4) which is common to said parts, when the flaps 5, 5' are closed.

When the flaps are closed, forces deriving from the intrinsic weight ofthe flaps 5, 5' and the ore resting on the flaps will act in the pivotpoints of the link system 8. The link system 8, and therewith also thelink system 8', is designed to lead these forces to the rotationalcentre of the link system 8, i.e. towards the point at which the two-armlever 17 rotates around the bearing block 16. Thus, no moments of forcewhich act to open the flaps 5, 5' will occur in the links 17, 18, 19,and any increase in truck load will merely act to enhance locking of thelink system 8.

One important advantage obtained when arranging the pivot points in amanner such that said points will lie on a common line when the flaps 5,5' are closed instead of allowing the pivot points to adopt a so-calledoverknee position, is that the self-locking effect can be nullified withthe application of a much smaller force and through a much shortermovement path. This facilitates and accelerates opening of the flaps 5,5' of the bottom discharge arrangement. The drawback with a link systemdesigned so that the pivot points will take an overknee position whenthe flaps are closed resides in the occurrence of negative forces in thesystem as a result of the influence exerted by the load. In the case ofsuch a link system, it is necessary to apply force to overcome saidgenerated negative forces when unlocking the link system, in addition tothe force normally required to unlock a link system in which the pivotpoints are not overkneed. The larger forces required for manoeuveringthe link system in this case require the provision of larger-sized linkarms and substantially longer lever arms, resulting in a more bulky linksystem.

The flaps are opened by moving the roller 14 on the lifting device 13from its lower to its upper position (FIGS. 3 and 4). The manner inwhich the roller 14 is moved is described in more detail in publicationSE 460 038 mentioned above. As the roller 14 moves upwards, the axle 12is rotated by the link arm 15. As the axle 12 rotates, the link arm 11is activated and, in turn, causes the two-arm lever 17 to rotateanti-clockwise, through the medium of the manoeuver arm 10.

It will be seen from FIG. 4 that the operating device 9 is also in alocked position when the flaps 5, 5' are closed, wherein the roller 14on the lifting device 13 of the operating device 9 is located in itsbottom end position. This locked state of the arrangement, achieved bythe construction of the links 10, 11, 15 and their mutually selectedpivot points, can only be released by causing the roller 14 to movetowards its upper end position.

When the two-arm lever 17 is turned anti-clockwise, there is generated amoment of force which, by virtue of the direction in which it acts,forces the pivot points between the links 17, 18, 19 of the link systemout of their locked positions and therewith release the link system 8.

It will be understood from the description referring to FIGS. 3 and 4that the links 17, 18, 19 of the link system 8 adopt a forceless stateof equilibrium when the flaps 5, 5' are closed. As the flaps move fromtheir closed position (FIG. 4) towards their open position (FIG. 3) inresponse to rotation of the two-arm lever 17, the pressure exerted onthe flaps by the goods contained in the goods container 2 will assist inopening the flaps 5, 5'.

Although not shown, the mutually proximal edges 21 of the flaps 5, 5'form a goods labyrinth when closed, therewith making it difficult forthe goods to escape between the flaps 5, 5'.

To achieve soft and gentle opening of the flaps 5, 5', one of the links13 is provided with a surface for abutment with an elastomeric dampingelement 21, abutment element, attached to the goods container 2.

It will be understood that the illustrated embodiment of the inventivebottom discharge arrangement in which the pivot points are arranged tolie on a common line does not limit the way in which the link system 8can be locked. For instance, the link system can be constructed in a wayin which the links take a slightly overkneed position when the flaps areclosed or a slightly instable position in which they are locked by theoperating device, both alternatives lying within the scope of theinventive concept. It will also be understood that it lies within thescope of the inventive concept to construct the bottom dischargearrangement in a manner which will enable the flaps to be manoeuvered bymeans of a single link system which acts on one flap. Such a bottomdischarge arrangement, however, would be larger in size and therewithmore bulky.

What is claimed is:
 1. A bottom discharge arrangement mounted to astructure having a goods containing space said arrangement comprises atleast one pair of flaps which are pivotally mounted on the goodscontainer at their mutually remote edges so as to be able to swingbetween an open and a closed position in a plane perpendicular to saidedges, the mutually opposing edges of the flaps lying sealingly againstone another when the flaps are closed, said flaps when open generallyform extensions of the opposing wall parts of the goods containerlocated above the flaps said arrangement including a link system whichis common to said flaps and which functions to maneuver the flapssimultaneously, said link system including a two-arm lever which ispivotally mounted at its center to an axle which is fixed in relation tosaid space and which is located centrally between the pivot axes of saidflaps, and wherein one end of the two-arm lever is pivotally connectedto a first link pivotally mounted on one of the flaps, and the other endof said lever is pivotally connected to a second link pivotally mountedon the other one of the flaps , when said flaps are closed, all pivotingpoints of said two-arm lever, first link and second link lie in anessentially forceless state of equilibrium in a common plane, whereinsaid state of equilibrium is locked by means of an operating devicecoacting with the link system; and in that the operating device is ameans connected to the two-arm lever for turning said two-arm leverabout said axle to bring the link system out of its state of equilibriumand therewith allow the flaps to open.
 2. The arrangement according toclaim 1, wherein the operating device includes a third link which ispivotally connected to the other end of the two-arm lever and the freeend of said third link being connected to a maneuvering link, whereinwhen the flaps are closed the pivot point between the third link and themaneuvering link will lie in said plane; and wherein when the flaps areclosed the pivot point between the third link and the two-arm lever islocated in a plane beneath the pivot axis of said pivot point, fixed inrelation to the space, so as to enable a flap-opening turning moment tobe applied to the two-arm lever.
 3. The arrangement according to claim2, wherein the arrangement includes a vertically extending liftingdevice which extends in the longitudinal direction of said structure;said structure including a track plane, and wherein said lifting deviceincluding a roller that can move between a bottom and a top end positionby virtue of its coaction with a guide rail arranged in said track planeof said structure; and in that the roller has connected thereto a linkarm which is pivotally connected to the maneuvering link and whichfunctions to lock said maneuvering link when the roller is in its bottomend position.
 4. The arrangement of claim 1 wherein said structurehaving said goods containing space comprises a goods container of an oretransporting railway truck.
 5. The arrangement of claim 1 wherein saidstructure, has a goods container which is a basket supported by anundercarriage.
 6. The arrangement of claim 5 wherein the arrangement ismounted on the undercarriage and includes a frame to which said flapsare pivotally connected.